The present invention relates to the conditioning of drinking water and more particularly to materials for introducing physiologically essential macro- and microelements into drinking water.
Known in the art is a material for conditioning drinking water, which material comprises dolomite-containing rock, containing, in weight percent: calcium, 20; magnesium, 11; iron, 0.002; copper, 0.01; cobalt, 0.001; nickel, 0.002; zinc, 0.01; chromium, 0.002; vanadium, 0.001. As water is passed through 1-5 mm granules of this mineral, ions of macroelements (calcium, magnesium) and of microalements (iron, copper, zinc), physiologically essential for human life, are introduced into the water (RF Patent. No. 2056358, IPC C02F 1/18, publ. 20.03.96).
Such material is disadvantageous in that other microelements cannot be introduced into it. The rate of passing water through a filling of such material is not high (1-2 l/h), because the physiologically essential elements are released only from the surface of the inorganic material.
A composition is known in the art for fluorinating (conditioning) drinking water, which composition comprises activated carbon and a material consisting of a cellulose ester (preferably cellulose acetate) and an inorganic compound containing fluorine ions (preferably calcium fluoride which is a poorly soluble compound). The granulometric composition of the material is 0.3-1.5 mm. The ratio of the components in the material, in weight percent, is 5-83:17-95 (RF Patent No. 2092451, IPC C02F 1/68, publ. 10.10.97). Such material makes it possible to saturate water with fluorine ions in an amount of 0.5-1.5 mg/l with the specific rate of water passage through the material of 0.5-5 minxe2x88x921.
This material is disadvantageous in that it is used only for introducing fluorine ions into the drinking wager. Weakly pronounced ion-exchange properties of the granules of the composition material rule out its simultaneous use for active removal of such a harmful admixture as heavy metal ions. Besides, the process of preparing this material is complicated, particularly because of using an inflammable liquid-acetone.
A material is also known for introducing physiologically essential ions into demineralized water, which material consists of granules of activated carbon, on the surface of whose pores poorly soluble inorganic compounds are present, which contain in their composition calcium and magnesium ions, releasable into the water. Depositing said inorganic poorly soluble compounds in the pores of activated carbon is accomplished by subjecting activated carbon to successive treatments with solutions of readily soluble substances which enter into exchange reactions resulting in precipitation of one of the reaction products. The activated carbon treated with each of the solutions has to be dried at a temperature of 150-200xc2x0 C. (Inventor""s Certificate of the USSR No. 1608138, IPC C02F 1/68, publ. 23.11.90).
This known material allows maintaining the concentration of calcium and magnesium ions in filtered water on the physiologically required level when the amount of the passed water is 30 l, the weight of the filling is 100 g and the rate of flow is 50 ml/min. The specific rate of filtration is 0.5 minxe2x88x921. Owing to its porous structure the material sorbs organic admixtures well enough and is also capable of retaining heavy metal ions by way of physical sorption. With the use of this material there is no steeping effect during breaks in operation.
The main disadvantage of such material is that it can be used only for introducing microelements such as magnesium, calcium, potassium. Other disadvantages of such material are: complexity of the process for preparing thereof, non-productive consumption of the reagents, as well as the absence of chemical sorption of heavy metal ions. The rate of water filtration through such material is not high.
The technical object of the present invention is therefore to provide a material which will ensure introducing into demineralized or drinking water physiologically essential micro- and macroelements with a stable release thereof into the water, simultaneous sorption of the admixtures of heavy metal ions and organic compounds from the water, and an increase in the rate of water filtration.
A material for introducing physiologically essential additives into drinking or demineralized water comprises an organic ion-exchanger having a porous structure in the air-dry state and inorganic poorly soluble compounds in the pores and on the surface thereof. The content of poorly soluble compounds in the material is 10-65 percent by weight.
Organic macrodorous or macromolecular net-work strongly and weakly acidic cation-exchangers with a polystyrene, polyacrylic and polymethacrylic matrix, as well as organic macroporous or macromolecular network high- and low-basic anion-exchangers with a polystyrene and polyacrylic matrix, or other agents similar in their structure and properties, having a total volume of pores of 0.1-1.0 cm3/g and 0.3-1.5 mm granules, are used as organic ion-exchangers having a porous structure in the air-dry state.
As inorganic poorly soluble compounds (PSC) the material comprises inorganic salts, oxides, hydroxides whose solubility is lower than 8 g/l and which have in their composition such elements essential for human life as Ca, Mg, F, Se, Zn, Cu, Fe, Mn, Cr, and others. The PSC comprising physiologically essential elements are formed as a result of exchange and redox reactions.
A process for the preparation of the material consists in successive treatment of an organic ion--exchanger with inorganic ionic compounds. The inorganic ion exchanger is treated first with an inorganic compound having a solubility higher than 8 g/l, for instance, with CaCl2, MgSO4, NaF, Na2SeO3, ZnSO4, CuSO4, FeSO4, MnSO4, KMnO4, Cr2(SO4)3, Na2SnO3, HCl, NaOH, KOH, K2CO3, HClO, one of the ions of the compounid passing to the ion-exchanger as a counterion. Then the ion-exchanger is treated with a second inorganic compound having a solubility higher than 8 g/l, one of whose ions reacts with the counterion of the ion-exchanger and forms an inorganic compound with a solubility a slower than 8 g/l (a poorly soluble compound) in the pores and on the surface of the ion-exchanger. Compounds presented hereinabove can be used as said second inorganic compound. In some Examples, for attaining the regularity and required level of the release of ions into the water, these operations are repeated 2-5 times, the PSC content in the material amounting to 10-65 percent by weight.